Abstract: 【Abstract】 Objective To investigate differences in intestinal microbiome between adult patients with psoriasis vulgaris and healthy individuals. Methods Fecal samples were collected from 22 patients with confirmed psoriasis vulgaris and 23 healthy controls in Hospital for Skin Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College from September 2017 to February 2018. The total DNA of intestinal flora was extracted and amplified, and the next-generation 16S rRNA gene-targeted sequencing was performed to analyze the diversity and distribution of intestinal flora. Species annotation and classification were performed according to Silva database, and rank sum test was used to analyze species differences among samples at different taxonomic ranks; QIIME software （Version 1.9.1） was used to calculate the number of operational taxonomic units (OTUs) and main indices of α diversity （Chao1 index, Shannon index and Simpson index）, and t test to analyze differences in indices; PCoA analysis was performed to analyze the difference in β diversity, and differences in microbial community composition structure were analyzed between the two groups by using permutational multivariate analysis of variance; rank sum test and linear discriminant analysis effect size （LEfSe） analysis were used to evaluate the species difference. Results No significant difference in the number of OTUs was observed between the psoriasis group （147.55 ± 57.07） and healthy control group（148.96 ± 50.45, t = 0.088, P = 0.930）. In addition, there were no significant differences in the Shannon index, Chao1 index or Simpson index between the psoriasis group （4.08 ± 0.80, 169.52 ± 63.17, 0.87 ± 0.07, respectively） and healthy control group （4.11 ± 0.94, 175.36 ± 53.59, 0.86 ± 0.90, respectively; t = 0.12, 0.34, 0.27, all P > 0.05）. PCoA analysis showed that the first and second principal components explained 49.8% and 15.62%, respectively, of the total variance between the psoriasis group and healthy control group, and permutational multivariate analysis of variance revealed that the β diversity significantly differed between the two groups （P = 0.011）. Different microbes between the psoriasis group and healthy control group included Firmicutes, Clostridia, Clostridiales, Erysipelotrichales and Erysipelotrichaceae, whose abundance significantly increased in the psoriasis group, as well as Epsilonproteobacteria, Campylobacterales, Campylobacteraceae, Campylobacter, Bacteroidales and Bacteroidaceae, whose abundance significantly increased in the healthy control group. Conclusion The intestinal microbiome differs between patients with psoriasis vulgaris and healthy individuals, which may serve as potential biomarkers for psoriasis vulgaris.

Key words: Psoriasis, Intestines, Biota, RNA, ribosomal, 16S, Gene sequencing